Purification and properties of human heart lactic dehydrogenase.

It was previously shown that the lactic dehydrogenases from various rabbit organs could be differentiated by immunochemical means (1). Vex11 and Ecarn (2) have reported that human serum contains lactic dchydrogenases with three differrnt electrophorctic mobilitics. Kaplan et al. (3), using the reaction rates in the presence of diphosphopyridinc nuclcotide and its analogues, have shown that the lactic dehydrogenases of human liver and skeletal muscle differ from those of human heart and kidney. In pursuance of immunochcmical studic>s designed to differentiate among the lactic dehydrogrnasrs from different human tissues, it was necessary to purify the enzymes from human organs. This communication reports thr method of purification and crystallization of lactic dchydrogcnasc from human heart, some of its properties, and the kinc%ic*s of its reaction with pyruvate, lactate, DPNH, DPN, 3-acc%ylpgridinc*DPN, and pyridinc-3-aldchydc-*DPN.